That depends upon how long or often it occurs. You should have a 24 hour monitor to see if there are any other arrythnias. Chronic AFIB can cause a clot do develop in the atrium...you need an echo. If. you are having symptoms such as dizziness, palpitations or syncope (fainting). P.S. get a second opinion. Mayo cardiology is fantastic. I travelled theer to be evaluated for a cardiomyopathy.. You are in good hands. I saw Dr Steve Omen. Be well